Droplet formation in microfluidics involves the flow of an immiscible liquid to form single droplets dispersed in a microfluidic channel. The control of the microfluidic droplet size produced in a microfluidic junction is far-reaching in several mechanical, biomedical and optical applications. This paper presents a numerical computation to study a droplet evolution in a T-junction microfluidic device. The normal flow velocity of the inlet is given for oil and water flows. The effect of  inlet velocity on droplet size and droplet generation frequency is observed using COMSOL Multiphysics software. To observe the variation in droplet size and generation frequency, the inlet velocities for water and oil phases are varied from 30mm/s to 70mm/s and 80mm/s to 120mm/s, respectively. The numerical results show that   the droplet volume decreases and the production frequency increases as the continuous phase inlet velocity is increased, consistent with conservation laws. The control of inlet velocities consequently manipulates the droplet size.

numerical simulation, droplet, T-junction, microfluidic.

Received: May 4, 2022; Accepted: June 7, 2022; Published: July 15, 2022

How to cite this article: Trong-Hy Tran, Thanh-Long Le, Duc-Thong Hong and Tran-Phu Nguyen, The effect of inlet velocities on the droplet size in T-junction microfluidic devices, JP Journal of Heat and Mass Transfer 28 (2022), 1-14. http://dx.doi.org/10.17654/0973576322030

This Open Access Article is Licensed under Creative Commons Attribution 4.0 International License

References:

[1] A. Shahidian, M. Ghassemi, J. Mohammadi and M. Hashemi, Application of microfluidics in cancer treatment, Bio-Engineering Approaches to Cancer Diagnosis and Treatment, Elsevier, 2020, pp. 219-250.
[2] M. Rabiee, N. N. Ghasemnia, N. Rabiee and M. Bagherzadeh, Microfluidic devices and drug delivery systems, Microfluidic Devices and Drug Delivery Systems, Academic Press, 2021, pp. 153-186.
[3] A. Dewan, J. Kim, R. H. McLean, S. A. Vanapalli and M. N. Karim, Growth kinetics of microalgae in microfluidic static droplet arrays, Biotechnology and Bioengineering 109(12) (2012), 2987‐2996.
[4] H. Song, J. D. Tice and R. F. Ismagilov, A microfluidic system for controlling reaction networks in time, Angewandte Chemie 115(7) (2003), 792‐796.
[5] C. Cramer, P. Fischer and E. J. Windhab, Drop formation in a co-flowing ambient fluid, Chem. Eng. Sci. 59 (2004), 3045-3058.
[6] A. Gupta and R. Kumar, Flow regime transition at high capillary numbers in a microfluidic T-junction: viscosity contrast and geometry effect, Phys. Fluids 22 (2010), 122001.
[7] A. Bedram, A. E. Darabi and A. Moosavi, Numerical investigation of an efficient method (T-junction with valve) for producing unequal-sized droplets in micro- and nano-fluidic systems, ASME J. Fluids Eng. 137 (2015), 031202.
[8] P. A. Romero and A. R. Abate, Flow focusing geometry generates droplets through a plug and squeeze mechanism, Lab Chip 12 (2012), 5130-5132.
[9] A. S. Opalski, T. S. Kaminski and P. Garstecki, Droplet microfluidics as a tool for the generation of granular matters and functional emulsions, KONA Powder Part. J. 36 (2019), 50-71.
[10] T. Glawdel, C. Elbuken and C. L. Ren, Droplet formation in microfluidic T-junction generators operating in the transitional regime, I. Experimental observations, Physical Review E 85 (2012), 016322.
[11] D. Huang, K. Wang, Y. Wang, H. Sun, X. Liang and T. Meng, Precise control for the size of droplet in T-junction microfluidic based on iterative learning method, J. Franklin Inst. 357 (2020), 5302-5316.
[12] T. Glawdel, C. Elbuken and C. L. Ren, Droplet formation in microfluidic T-junction generators operating in the transitional regime, II. Modeling, Physical Review E 85 (2012), 016323.
[13] E. C. Santos, A. Ładosz, G. M. Maggioni, P. R. Rohr and M. Mazzotti, Characterization of shapes and volumes of droplets generated in PDMS T-junctions to study nucleation, Chemical Engineering Research and Design 138 (2018), 444-457.
[14] M. Y. A. Jamalabadi, M. D. Shirazi, Ali Kosar and M. S. Shadloo, Effect of injection angle, density ratio, and viscosity on droplet formation in a microfluidic T-junction, Theoretical and Applied Mechanics Letters 7 (2017), 243-251.
[15] J. Xu, S. Li, J. Tan and G. Luo, Correlations of droplet formation in T-junction microfluidic devices: from squeezing to dripping, Microfluidics and Nanofluidics 5(6) (2008), 711-717.
[16] E. Olsson and G. Kreiss, A conservative level set method for two phase flow, J. Comput. Phys. 210 (2005), 225-246.
[17] T.-L. Le, J.-C. Chen, B.-C. Shen, F.-S. Hwu and H.-B. Nguyen, Numerical investigation of the thermocapillary actuation behavior of a droplet in a microchannel, Int. J. Heat Mass Transfer 83 (2015), 721-730.
[18] T.-L. Le, J.-C. Chen, F.-S. Hwu and H.-B. Nguyen, Numerical study of the migration of a silicone plug inside a capillary tube subjected to an unsteady wall temperature gradient, Int. J. Heat Mass Transfer 97 (2016), 439-449.
[19] T.-L. Le, J.-C. Chen and H.-B. Nguyen, Numerical study of the thermocapillary droplet migration in a microchannel under a blocking effect from the heated wall, Appl. Thermal Eng. 122 (2017), 820-830.
[20] T.-L. Le, J.-C. Chen and H.-B. Nguyen, Numerical investigation of the forward and backward thermocapillary motion of a water droplet in a microchannel by two periodically activated heat sources, Numerical Heat Transfer, Part A: Applications 79(2) (2020), 146-162.
[21] T.-L. Le and N. T. Tien, A CFD study on hydraulic and disinfection efficiencies of the body sterilization chamber, Annals of the Romanian Society for Cell Biology 25(2) (2021), 3998-4004.
[22] T.-L. Le and T. D. Hong, Computational fluid dynamics study of the hydrodynamic characteristics of a torpedo-shaped underwater glider, Fluids 6 (2021), 252.
[23] K. Loizou, V.-L. Wong and B. Hewakandamby, Examining the effect of flow rate ratio on droplet generation and regime transition in a microfluidic T-junction at constant capillary numbers, Inventions 3(3) (2018), 54.
[24] M. N. Kashid, A. Renken and L. Kiwi-Minsker, CFD modelling of liquid-liquid multiphase microstructured reactor: slug flow generation, Chemical Engineering Research and Design 88(3) (2010), 362-368.